1. Field of the Invention
The present invention relates to an adjustable tray, and more particularly to an adjustable keyboard tray for a computer desk, which can be conveniently adjusted.
2. Description of Related Art
With reference to FIGS. 9-11, a conventional adjustable keyboard tray for a desk comprises a mounting bracket (80), a slide (81), a first adjusting arm (90), a second adjusting arm (82) and a keyboard plate (86). The mounting bracket (80) is adapted to be attached to the bottom of a desktop (70). The slide (81) is movably mounted on the mounting bracket (80). The first adjusting arm (90) and the second adjusting arm (82) are pivotally attached to opposite sides of the slide (81). The keyboard plate (86) is adjustably connected to the adjusting arms (90, 82).
With reference to FIGS. 9 and 10, the degree to which the keyboard plate (86) is inclined is adjusted by pivoting the keyboard plate (86) relative to the first and second adjusting arms (82, 90). The first and second adjusting arms (82, 90) are mirror images of each other, and the principle of operation is the same for both. The first adjusting arm (90) is composed of an upper rod (90a) and a lower rod (90b). Both the upper and lower rods (90a, 90b) have two ends. One end of each rod (90a, 90b) is pivotally attached to the slide (81), and the other end is pivotally attached to a side plate (not numbered) of the keyboard plate (86). The lower rod (90b) is parallel to the upper rod (90a) and has one end pivotally attached on the slide (81). The other end of the lower rod (90b) is movably connected to the keyboard plate (86). A first curved slot (88) is defined in the side plate of the keyboard plate (86), and a first pin (92) formed on the lower rod (90b) sliding to the first curved slot (88). Therefore, when a user adjusts the angle of the keyboard plate (86), two first knobs (87, in FIG. 9) mounted on the first adjusting arm (90) and the second adjusting arm (82) respectively are rotated to release the first pin (92). Then, the first pin (92) moves along the first curved slot (88) to pivot the keyboard plate (86) around a pivot pin (91) on the upper rod (90a) to adjust the angle of the keyboard plate (86). When the keyboard plate (86) reaches a desired angle, the knobs (91) are tightened to lock the first pin (92) again to hold the keyboard plate (86) in position. Additionally, a second curved slot (89) is defined in the side plate of the keyboard plate (86), and a second pin (85) formed in a middle section of the lower rod (90b) is mounted in the second curved slot (89).
With reference to FIG. 11, The height of the keyboard plate (86) is adjusted by changing the position of the second pin (85) in the second curved slot (89). Two second knobs (93, in FIG. 9) are secured on the second adjusting arm (82) and the first adjusting arm (90) respectively to lock the second sliding pin (85). Therefore, when the second knobs (89) are loosened to release the second sliding pin (85), the second sliding pin (85) is able to slide in the second curved slot (89). Meanwhile, the upper rod (82a) and the lower rod (82b) simultaneously pivotal on the slide (81) whereby the height of the keyboard plate (86) is adjusted.
Two pairs of knobs (87, 93) must be loosened and tightened to adjust the angle and height of the conventional adjustable keyboard tray. Therefore, adjustment of the conventional adjustable keyboard tray requires at least two operational steps which makes adjusting the position of the keyboard tray troublesome.
To obviate and/or alleviate the problem with the conventional adjustable keyboard tray, the present invention provides an adjustable keyboard tray that requires only one operational step to adjust the height and angle of the keyboard tray.
The main objective of the invention is to provide an adjustable keyboard tray, which is easily adjusted.
Other advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.